Atmospheric benzenoid emissions from plants rival those from fossil fuels

Misztal, P. and Hewitt, C. N. and Wildt, J. and D. Blande, J. and Eller, A.S.D. and Fares, S. and R. Gentner, D. and B. Gilman, J. and Graus, M. and Greenberg, J. and Guenther, A. and Hansel, A and Harley, Peter and Huang, M. and Jardine, K. and Karl, T. and Kaser, L. and Keutsch, F.N. and Kiendler-Scharr, A. and Kleist, E. and Lerner, B.M. and Li, T. and Mak, J. and Nölscher, A.C. and Schnitzhofer, R. and Sinha, V. and Thornton, B. and Warneke, C. and Wegener, F. and Werner, C. and Williams, J. and Worton, D.R. and Yassaa, N. and Goldstein, A.H. (2015) Atmospheric benzenoid emissions from plants rival those from fossil fuels. Scientific Reports, 5: 21064. ISSN 2045-2322

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Abstract

Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y-1), pointing to the importance of these natural emissions in atmospheric physics and chemistry.